Oil well pump actuating mechanism

ABSTRACT

A mechanical movement characterized by structural mechanism operative to convert reciprocating motion of a crank-actuated connecting rod assembly to straight-line reciprocating motion of another part; the mechanism being especially designed but not limited--for operating the sucker rod of a deep well oil pump.

United States Patent Erich [45 Dec. 19, 1972 [54] OIL WELL PUMP ACTUATING MECHANISM [72] Inventor: Reuben R. Erich, Fayetteville, Ark.

[73] Assignee: Richard R. Erich, Fayettevi1le,, Ark.

', a part interest [22] Filed Dec. 29, 1970 [21] App1.No.: 102,303

[52] US. Cl ..74/4l, 74/583 [51] Int. Cl. ..G05g 1/00 [58] Field of Search ..74/41, 44, 583; 166/75 [56] References Cited UNITED STATES PATENTS 1,363,021 12/1920 S1ee ..74/583 2,153,558 4/1939 Gruss ..74/583 Gates et a1 ..74/583 3,051,237 8/1962 Liles, Jr. et a1. ..74/583 1,761,330 6/1930 Davis ..74/41 2,502,057 3/1950 Mitchell ..74/4l 3,209,605 10/1965 Scoggins, Jr ..74/41 731,935 6/1903 Mu1ler...., ..74/41 24,822 7/ 1 859 Robbins ..74/44 Primary Examiner-Milton Kaufman Assistant ExaminerWesley Ratliff, Jr. Attorney-Webster & Webster [57] ABSTRACT A mechanical movement characterized by structural mechanism operative to convert reciprocating motion of a crank-actuated connecting rod assembly to straight-line reciprocating motion of another part; the

mechanism being especially designed but not limited-- for operating the sucker rod of a deep well oil pump.

5 Claims, 6'Drawing Figures PATENTEnum 19 I972 3.706 234 sum 1 or 3 Wyn/7'02 Piuai/v A. 59/01 PATENTED DEC 19 I972 SHEET 3 0F 3 OIL WELL PUMP ACTUATING MECHANISM BACKGROUND OF THE INVENTION Oil well pump actuating mechanism of the walkingbeam type commonly causes a substantially increased power demand at the start of the upward pumping stroke of the rod string, and at which time not only must such rod string be started in motion but also movement of a high column of oil must be initiated. The present invention was conceived in view of the foregoing disadvantage of the conventional pump-actuating mechanism, and to provide other distinct advantages as will hereinafter appear.

SUMMARY OF THE INVENTION The present invention provides, as a major object, an oil well pump actuating mechanism which is operative tomost effectively convert reciprocating'motion of a crank-actuated connecting rod assembly to straightline reciprocating movement-vertically-of the sucker rod of the pump; such mechanism, which includes a novel motion-translating unit, also functioning in a manner to produce a low accelerating value during the start of the upward pumping stroke of the rod string, and this reduces the otherwise appreciably increased power demand at such time.

The present invention provides, as another object, an oil well pump actuating mechanism-as in the preceding paragraph, and including a counterweighted crankshaft which -actuates the connecting rod assemblyembodying a novel device, in the form of what may be termed an air balance, operative to absorb the effect of the motion change of the rod string at the end of each stroke thereof, and to damp the impact of such rod string as it reaches the bottom of the well. Such device also functions in cooperation with the counterweights of the crankshaft to aid in starting the rod string in motion at the beginning of the upward pumping stroke thereof.

The present invention provides, as a further object, an oil well pump actuating mechanism which is designed for ease and economy of manufacture.

The present invention provides, as a still further object, a practical, reliable, and durable oil well pump actuating mechanism and one which is exceedingly effective for the purpose for which it is designed.

BRIEF DESCRIPTION OF THE DRAWINGS:

FIG. 1 is a plan view of the pump-actuating mechanism.

FIG. 2 is a side elevation of such mechanism showing the parts in the position occupied thereby at the end of the downward return stroke of the sucker rod and, of course, at the start of its upward pumping stroke.

FIG. 3 is a cross section taken on line 3-3 of FIG. 2.

FIG. 4 is a view similar to FIG. 2 but shows theposition of the parts of the mechanism when the sucker rod is in an intermediate position during its upward pumping stroke.

FIG. 5 is a view similar to FIG. 2 but shows the position of the parts upon the sucker rod reaching the end of its upward pumping stroke.

FIG. 6 is a view similar to FIG. 2 but shows the position of the parts when the sucker rod is in an intermediate position during its downward return stroke.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now more particularly to the drawings and to the characters of referencemarked thereon, the present invention comprises a base frame 1 disposed adjacent but toone side of an oil well casing 2 fitted with a packing gland 3 through which extends the upwardly projecting sucker rod 4 of the pumping rod string. p

A rail 5 is journaled, as at 6, on the base frame 1 at the end adjacent the sucker rod 4, and such rail extends longitudinally at an upward and outward incline over said sucker rod; the rail normally being fixed to a supporting post 7 on such base frame 1. The outer portion of the rail, and'which maybe termed the working portion, is disposed at an upward incline of 45 degrees relative to horizontal.

Intermediate its ends, the base frame 1 supports-by means of standards 8-a transverse crankshaft 9 which includes two crank throws 10 attached to corresponding connecting rods 11 which extend from such crank throws at an upward and outward incline in the same directionas the rail 5. Outwardly of each crank throw 10, the crankshaft 9 is provided with a counterweight 12; the latter being positioned at top dead center at the start of each pumping cycle, and at which time said crank throws extend at a downward and rearward incline as shown in FIG. 2.

The crankshaft 9 is driven, by means of a multiple endless belt unit 13, from a reduction gear box 14 powered by an electric motor 15; such gear box and motor being suitably mounted on base frame 1 at the end remote from sucker rod 4.

At their forward or upper ends, the connecting rods 11 are journaled on the ends of a cross shaft 16, and an end-flanged roller 17 is carried on such cross shaft centrally of its ends. Such roller rides on the 45 degree working portion of the rail 5; the roller being positioned at the lower end of such portion of the rail at the start of each pumping cycle.

The cross shaft 16 is also connected to a motiontranslating unit, indicated generally at 18, and. which comprises the following:

A triangular plate 19 is disposed in spaced relation on each side of the rail 5, and one point A of each such plate is journaled in connection with the cross shaft 16 inwardly of the related connecting rod 1 1. At the start of each pumping cycle, such point A of the triangular plates 19 is disposed rearwardly of and above a second point B, and rearwardly of and horizontally alined with a third point C. See FIG. 2.

Point B of each triangular plate 19 is connected by a suitable pivot 20 to the upper end of a suspension link 21, while the lower ends of such links aresecured to a cross bar 22 to which the upper end of the sucker rod 4 is centrally attached. v

Point C of each triangular plate is journaled on the related end of a cross shaft 23 of a device, indicated generally at 24, which may be termed an air balance cylinder unit and which is constructed as follows:

An elongated, closed-top, open-bottom cylinder 25 is disposed in spaced relation below the rail 5 ahead of the links 21; such cylinder being fixedly mounted with its axis at a right angle to said rail, and hence is forwardly and downwardly inclined. The cylinder 25 is maintained in rigid connection with the rail 5 by attachment legs 26 spaced apart and located above and below the extended axis of such cylinder.

A piston 27 is disposed in the cylinder for reciprocation therein, and a piston rod 28 extends from the piston at an upward and rearward incline to rigid connection with the underside of cross shaft 23. Transversely spaced guide rods 29 are fixed on the topside of cross shaft 23 laterally in opposite directions from the extended axis of cylinder 25, and such guide rods project upwardly and in slidable relation through a guide block 30 fixed transversely on the bottom of rail 5.

With the foregoing assembly of cylinder 25, piston 27, piston rod 28, cross shaft 23; guide rods 29, and guide block 30, point C of the connected triangular plates is constrained from movement in any direction other than axially of the cylinder. Such point C can, however, moveto a limited extentaxially of the cylinder and so that the piston 27 can be reciprocated, in the cylinder, through a predetermined stroke. When the piston 27 is in its lowermost position in the'cylinder, ports 31 therein are uncovered and opened to atmosphere. See FIGS. 4 and 6.

In operation ofthe above-described oil well pump actuating mechanism, the parts-at the start of each pumping cycle and when the sucker rod 4 is in its lowermost position-are as shown in FIG. 2; points A and B'being alined in a plane extending at a right angle to rail 5, while points B and C are alined in a plane extending parallel to said rail. With initial rotation of the crankshaft 9 in the direction indicated, the connecting rods 11 are thrust forward, and roller 17 is started in motion up the working portion of the inclined rail 5. This causes, in effect, a swinging motion of the connected triangular plates 19 in a direction such that as point A moves in a straight line up the rail 5, point B (with point C moving only a limited distance axially of cylinder 25 and serving as an anchor point) is raised vertically, and which pulls straight upwardly on the sucker rod 4 and initiates the upward pumping stroke of the rod string. This motion continues through an intermediate position of the parts (as shown in FIG. 4) and until the connecting rods 11 and roller 17 reach a position of maximum advance on rail 5, and at which time the sucker rod 4 is fully raised and the pumping stroke is completed (as shown in FIG. 5).

At completion of each pumping stroke, the triangular plates 19 have assumed a position with points B and C in alinement in a plane extending at a right angle to rail 5, while points A and C are alined in a vertical plane. Thus, because of the geometries involved, the plates 19-as they are rotated about point B as an axis-produce a true vertical lifting action, and as requisite for straight-line movement of the sucker rod 4 and the connected rod string.

Upon completion of each pumping stroke, the connecting rodsare drawn rearwardly to starting position, resulting in rotation of the plates 19 in reverse to that described above, and which produces a downward return stroke of the sucker rod and connected rod counterweights 12 are in their top position and the piston 27 is'raised in cylinder 25 with a quantity of air highly compressed between the piston and the closed upper end of the cylinder. Consequently, as the connecting rods 1 1 are initially thrust forwardly to start the next pumping cycle, the counterweights ,12 swing downward and at the same time the air compressed in cylinder 25 tends to lower piston 27 and hence to lower point C of the triangular plates 19. Both of these forces, therefore, effectively aid in initiating each upward pumping stroke of the sucker rod and connected rod string without causing a substantially increased load on the motor 15.

As the mechanism reaches its intermediate position during the upward pumping stroke (see FIG. 4), the piston 27 reaches its lowermost position and exposes ports 31 to atmosphere, and ventsv the cylinder; the piston then at oncereversing and beginning to move upwardly in cylinder 25. By the time the upward-pumping stroke is completed (with connecting rods 11 fully advanced), the piston is in its raised position and has compressed another quantity of air between such piston and the closed upper end of the cylinder. Suchair-compressing action serves to cushion the stopping motion of the sucker rod and connected rod string upon completion of the pumping stroke. Similarly, when the sucker rod and connected rod string complete the downward return stroke of each cycle, air is compressed by the piston 27 to produce a like cushioning effect.

Further, the action of the fair balance is such that, at the end of each stroke, there is an absorption of the effect of the change of direction of motion of the sucker rod and connected rod string.

It will be recognized that for each two-stroke pumping cycle of the sucker rod, there is a four-stroke cycle of the piston 27 of the air balance 24 in order to accomplishthe described functions of the latter.

An oil well pump actuating mechanism constructed in accordance with the present invention produces a most effective cycling of the sucker rod and connected rod string, and without imposing undue power demands on the power drive unit of such mechanism.

From the foregoing description, it will be readily seen that there has been produced suchan oil well pump actuating mechanism as substantially fulfills the objects of the invention, as set forth herein.

While this specification sets forth in detail the present and preferred construction of the oil well pump actuating mechanism, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

I claim 1. An actuating mechanism, for an oil well pump in-. cluding a vertical sucker rod, comprising a base frame disposed adjacent the sucker rod, a longitudinal rail secured to the base frame and extending therefrom at an upward and outward incline in spaced relation to and above the sucker rod, a crankshaft journaled transversely on the base frame, an element reciprocable on the rail in guided relation, a connecting rod extending between the crankshaft and such element, and a motion-translating unit connected between such element and the sucker rod operative to translate longitudinal reciprocable motion of the element on the rail to verti cal reciprocating motion of the sucker rod through a cycle having an upward pumping stroke and a downward return stroke; the motion translating unit including a member disposed for vertical turning motion clear of the rail and having three points in triangular array, a first point and a second point being horizontally alined while the third point is located below and centrally between the first point and second point when the connecting rod is retracted, the connecting rod being attached to said member at the first point, means pivoting the second point in association with the rail and for limited lineal motion only in a direction at a right angle to the rail, and other means coupling the sucker rod to the member at said third point.

2. A mechanism, as in claim 1, in which the element is a roller, and said member is a plate in the form of a triangle.

3. A mechanism, as in claim 1, including a supplementary-force device embodying a cylinder having a piston movable therein to produce a force reaction by fluid compression; said supplementary-force device being arranged in connection with the motion-translating unit and operative to provide an additive force to said motion-translating unit upon initiation thereby of the upward pumping stroke and the downward return stroke of the sucker rod; the pivot for said second point being carried by such supplementary-force device.

4. A mechanism, as in claim 3, in which the cylinder of the supplementary-force device is fixed to the rail with the cylinder axis at a right angle thereto, the piston being reciprocable in the cylinder, a piston rod extending axially from the piston and cylinder axially thereof, said piston rod being guided for limited axial movement only, and the pivot for said second point being carried by such piston rod; the piston forcefully compressing air in the cylinder upon completion of each stroke of the sucker rod and opening such cylinder to atmosphere at an intermediate point in each such stroke. 5. An actuating mechanism, for an oil well pump including a vertical sucker rod, comprising a base frame disposed adjacent the sucker rod, a longitudinal rail secured to the base frame and extending therefrom at an upward and outward incline in spaced relation to and above the sucker rod, a crankshaft journaled transversely on the base frame, an element reciprocable on the rail in guided relation, a connecting rod extending between the crankshaft and such element, and a motion-translating unit connected between such element and the sucker rod operative to translate longitudinal reciprocable motion of the element on the rail to vertical reciprocating motion of the sucker rod through a cycle having an upward pumping stroke and a downward return stroke; said element comprising a roller which rides such rail, and the motion-translating unit including connected but transversely spaced, laterally matching triangular plates between which the rail extends, each triangular plate having a first point and a second point horizontally alined while a third point is located below and centrally between the first point and second point when the-connecting rod is retracted, the connecting rod being attached to said plates at their first points, means pivoting the second points in association with the rail and for limited lineal motion only in a direction at a ri ht angle to the rail, and other means coupling the suc er ro to the plates at said third points. 

1. An actuating mechanism, for an oil well pump including a vertical sucker rod, comprising a base frame disposed adjacent the sucker rod, a longitudinal rail secured to the base frame and extending therefrom at an upward and outward incline in spaced relation to and above the sucker rod, a crankshaft journaled transversely on the base frame, an element reciprocable on the rail in guided relation, a connecting rod extending between the crankshaft and such element, and a motion-translating unit connected between such element and the sucker rod operative to translate longitudinal reciprocable motion of the element on the rail to vertical reciprocating motion of the sucker rod through a cycle having an upward pumping stroke and a downward return stroke; the motion translating unit including a member disposed for vertical turning motion clear of the rail and having three points in triangular array, a first point and a second point being horizontally alined while the third point is located below and centrally between the first point and second point when the connecting rod is retracted, the connecting rod being attached to said member at the first point, means pivoting the second point in association with the rail and for limited lineal motion only in a direction at a right angle to the rail, and other means coupling the sucker rod to the member at said third point.
 2. A mechanism, as in claim 1, in which the element is a roller, and said member is a plate in the form of a triangle.
 3. A mechanism, as in claim 1, including a supplementary-force device embodying a cylinder having a piston movable therein to produce a force reaction by fluid compression; said supplementary-force device being arranged in connection with the motion-translating unit and operative to provide an additive force to said motion-translating unit upon initiation thereby of the upward pumping stroke and the downward return stroke of the sucker rod; the pivot for said second point being carried by such supplementary-force device.
 4. A mechanism, as in claim 3, in which the cylinder of the supplementary-force device is fixed to the rail with the cylinder axis at a right angle thereto, the piston being reciprocable in the cylinder, a piston rod extending axially from the piston and cylinder axially thereof, said piston rod being guided for limited axial movement only, and the pivot for said second point being carried by such piston rod; the piston forcefully compressing air in the cylinder upon completion of each stroke of the sucker rod and opening such cylinder to atmosphere aT an intermediate point in each such stroke.
 5. An actuating mechanism, for an oil well pump including a vertical sucker rod, comprising a base frame disposed adjacent the sucker rod, a longitudinal rail secured to the base frame and extending therefrom at an upward and outward incline in spaced relation to and above the sucker rod, a crankshaft journaled transversely on the base frame, an element reciprocable on the rail in guided relation, a connecting rod extending between the crankshaft and such element, and a motion-translating unit connected between such element and the sucker rod operative to translate longitudinal reciprocable motion of the element on the rail to vertical reciprocating motion of the sucker rod through a cycle having an upward pumping stroke and a downward return stroke; said element comprising a roller which rides such rail, and the motion-translating unit including connected but transversely spaced, laterally matching triangular plates between which the rail extends, each triangular plate having a first point and a second point horizontally alined while a third point is located below and centrally between the first point and second point when the connecting rod is retracted, the connecting rod being attached to said plates at their first points, means pivoting the second points in association with the rail and for limited lineal motion only in a direction at a right angle to the rail, and other means coupling the sucker rod to the plates at said third points. 